1. Field of the Invention
This invention relates to helicopter rotors and more particularly to cross-beam rotors wherein a blade is suspended from the ends of one or more unidirectional, composite spars and in which the pitch control mechanism passes through the rotor at the center of rotation. More particularly, the pitch control shaft passes through a floating centering member supported in a selectively shaped hole through the spar so as to substantially reduce the stress concentration factor across the spar at the hole and react unbalanced blade centrifugal loads.
2. Description of the Prior Art
It is known in the prior art to control the pitch of rotors of this type through pitch control mechanism located external to the spar which requires no hole but produces an unacceptably heavy control mechanism which creates substantial parasitic and aerodynamic drag and is prone to ballistic damage. For example, in earlier helicopter rotor constructions a plurality of pitch change servos were supported external of the rotor spar and connected to each blade through a swashplate or other conventional pitch change mechanism to effect blade pitch variation.